Class TiXmlHandle
Defined in File tinyxml.h
Class Documentation
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class TiXmlHandle
A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing. Note that TiXmlHandle is not part of the TinyXml DOM structure. It is a separate utility class.
Take an example:
<Document> <Element attributeA = "valueA"> <Child attributeB = "value1" /> <Child attributeB = "value2" /> </Element> <Document>
Assuming you want the value of “attributeB” in the 2nd “Child” element, it’s very easy to write a lot of code that looks like:
TiXmlElement* root = document.FirstChildElement( "Document" ); if ( root ) { TiXmlElement* element = root->FirstChildElement( "Element" ); if ( element ) { TiXmlElement* child = element->FirstChildElement( "Child" ); if ( child ) { TiXmlElement* child2 = child->NextSiblingElement( "Child" ); if ( child2 ) { // Finally do something useful.
And that doesn’t even cover “else” cases. TiXmlHandle addresses the verbosity of such code. A TiXmlHandle checks for null pointers so it is perfectly safe and correct to use:
TiXmlHandle docHandle( &document ); TiXmlElement* child2 = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", 1 ).ToElement(); if ( child2 ) { // do something useful
Which is MUCH more concise and useful.
It is also safe to copy handles - internally they are nothing more than node pointers.
TiXmlHandle handleCopy = handle;
What they should not be used for is iteration:
int i=0; while ( true ) { TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", i ).ToElement(); if ( !child ) break; // do something ++i; }
It seems reasonable, but it is in fact two embedded while loops. The Child method is a linear walk to find the element, so this code would iterate much more than it needs to. Instead, prefer:
TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).FirstChild( "Child" ).ToElement(); for( child; child; child=child->NextSiblingElement() ) { // do something }
Public Functions
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inline TiXmlHandle(TiXmlNode *_node)
Create a handle from any node (at any depth of the tree.) This can be a null pointer.
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inline TiXmlHandle(const TiXmlHandle &ref)
Copy constructor.
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inline TiXmlHandle operator=(const TiXmlHandle &ref)
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TiXmlHandle FirstChild() const
Return a handle to the first child node.
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TiXmlHandle FirstChild(const char *value) const
Return a handle to the first child node with the given name.
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TiXmlHandle FirstChildElement() const
Return a handle to the first child element.
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TiXmlHandle FirstChildElement(const char *value) const
Return a handle to the first child element with the given name.
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TiXmlHandle Child(const char *value, int index) const
Return a handle to the “index” child with the given name. The first child is 0, the second 1, etc.
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TiXmlHandle Child(int index) const
Return a handle to the “index” child. The first child is 0, the second 1, etc.
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TiXmlHandle ChildElement(const char *value, int index) const
Return a handle to the “index” child element with the given name. The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted.
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TiXmlHandle ChildElement(int index) const
Return a handle to the “index” child element. The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted.
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inline TiXmlElement *ToElement() const
Return the handle as a TiXmlElement. This may return null.
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inline TiXmlUnknown *ToUnknown() const
Return the handle as a TiXmlUnknown. This may return null.
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inline TiXmlNode *Node() const
- Deprecated:
use ToNode. Return the handle as a TiXmlNode. This may return null.
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inline TiXmlElement *Element() const
- Deprecated:
use ToElement. Return the handle as a TiXmlElement. This may return null.
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inline TiXmlText *Text() const
- Deprecated:
use ToText() Return the handle as a TiXmlText. This may return null.
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inline TiXmlUnknown *Unknown() const
- Deprecated:
use ToUnknown() Return the handle as a TiXmlUnknown. This may return null.
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inline TiXmlHandle(TiXmlNode *_node)